1. Technical Field
The invention relates to inspecting a discharge state of a liquid discharging apparatus.
2. Related Art
Ink jet type printers perform printing by discharging ink inside a cavity. The ink thickens after drying. When the ink inside the cavity is thickened, there are times when this causes discharge failures. In addition, when bubbles are included in the ink inside the cavity or when paper dust is attached to the nozzles which discharge the ink, there are times when this causes discharge failures. Thus, it is preferable to inspect the discharge state of the ink.
JP-A-2004-276544 (see FIG. 31) discloses a method where the discharge state is determined by applying vibration to the ink inside the cavity using a piezoelectric element and detecting the behavior of ink with respect to the residual vibration thereof.
Here, the behavior of the ink is detected according to electromotive force of the piezoelectric element. Accordingly, it is necessary to apply a driving signal for inspecting the piezoelectric element in the step where the vibration is applied to the ink and to extract the electromotive force from the piezoelectric element in the step where the residual vibration of the ink is inspected. In more detail, JP-A-2004-276544 (see FIG. 31) discloses a switch which selects a driver which supplies a driving signal and a head abnormality detecting unit which detects abnormalities in a head based on electromotive force and which connects the driver and the head abnormality detecting unit with the piezoelectric element.
However, with respect to a driving signal which has a large amplitude, the electromotive force of the piezoelectric element according to the residual vibration has a small amplitude. Although it is desired to draw a wiring in consideration of properties of the signal, JP-A-2004-276544 (see FIG. 31) does not disclose the point.